This invention relates to an apparatus and method for removing meat from bones, and more particularly, to an apparatus and method for removing substantially all meat and other soft tissue from bones while leaving the bones substantially intact. The apparatus and method may be applied advantageously to recover any type of meat but is particularly useful in recovering beef or pork.
The process of producing commercial meat products from whole carcasses includes first removing larger cuts of meat manually with a knife or other suitable tool. This manual first step recovers the bulk of the meat from the carcass but leaves small amounts of meat attached to the remaining bones. Although these small amounts of meat may be removed from the bones and combined to produce commercial meat products, such small amounts cannot be removed economically by hand.
A number of techniques have been developed to recover the meat remaining on bones after the larger cuts have been removed manually. U.S. Pat. No. 3,722,032 to Draper et al. and U.S. Pat. No. 3,671,999 to Downs were both directed to devices for removing meat from bones using jets of liquid. Both of these patents taught mounting the bones or carcasses on a suitable conveyor and then conveying the bones or carcasses past a series of high pressure water jets that each acted as a knife to cut through the meat and separate the meat from the bone to which it was attached. However, meat or nutrients from the meat tended to dissolve in the water utilized in these water jet techniques and such dissolved meat and nutrients were themselves difficult to recover. The loss of nutrients to the water also lowered the quality of the recovered meat pieces.
U.S. Pat. No. 2,784,446 to Beatty was directed to a device that used steel shots to remove meat from bones. The shots were directed to impinge upon a carcass to blast away meat and other tissue remaining on the bones. The shots, however, not only themselves contaminated the meat removed from the carcass, but also broke the bones in the carcass to produce bone fragments that also contaminated the meat.
In the device disclosed in my U.S. Pat. No. 4,186,216, small frozen meat particles were accelerated to a relatively high velocity and then impinged against bones to remove meat remaining attached after the larger cuts were removed manually. The bones were contained in an impingement housing that was adapted to move the bones so as to expose their various surfaces to the streams of high velocity frozen meat particles. Although, this frozen meat particle impinging device solved the problem of having to introduce foreign substances into the meat being removed, the use of frozen meat particles raised new problems. Freezing the meat and producing the small particles was relatively expensive and subjected at least a portion of the recovered meat to freeze/thaw cycles that reduced the quality of the product.
U.S. Pat. No. 3,906,118 to McFarland was directed to a device for separating edible flesh from normally inedible components of poultry or fish. In the McFarland device, bones with meat attached thereto were first ground and the resulting ground material was then conveyed through a perforated conduit. As the ground material was conveyed through the perforated conduit, it was also compressed against the perforations to force the meat and other soft tissue therethrough, leaving most of the ground bone and other hard components to act as a filter mat against the perforations, and finally, to be conveyed the length of the conduit to a discharge end. The required compression was provided by either the conveying mechanism alone, or by introducing the ground bone and soft tissue into the perforated conduit under pressure in addition to the compression provided by the conveyor. However, the grinding and straining technique taught by McFarland allowed fine bone pieces and pieces of bone marrow to pass through the perforations along with the meat, and reduced the quality and marketability of the recovered meat. The reduced quality was particularly acute when the meat being processed was beef or pork.